The present invention relates to a Faraday rotator assembly, more particularly to a Faraday rotator assembly provided with means which can prevent irregular fluctuation of the magnetic domain in the Faraday rotator on reversing the direction of the Faraday rotation.
As is well known, Faraday rotators made of, for example, a single crystal of yttrium-iron-garnet (YIG) can be used in optical switches for optical communications since they enable effective selection of optical paths.
Such optical switches make use of the Faraday rotation of linearly polarized light passing through the Faraday rotator. The clockwise or counterclockwise direction of rotation due to the Faraday effect depends on whether the direction of the external magnetic field applied to the YIG is the same as or opposite to the direction of light travel, respectively. Therefore, to reverse the rotation due to the Faraday effect, the direction of the magnetic field applied to the YIG must be reversed.
The conventional means for reversing the direction of the magnetic field has the problem of irregular fluctuation of the magnetic domain in the Faraday rotator during the reversal. This results in dispersion of the light and unusual fluctuation of the output light intensity or level, thus obstructing effective optical communications.